JP2002097571A - Method and apparatus for manufacturing functional film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quantitatively and promptly control a transmittance of a functional film. SOLUTION: This method for manufacturing the functional film, which forms an optical thin film on a film substrate with reactive sputtering to form the functional film 1, which spouts reactive gas to the film substrate of a basement of the functional film 1, comprises measuring a spectral transmittance of the functional film after forming the optical thin film, and varying a injecting quantity in injecting the reactive gas, based on the measured result of the spectral transmittance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a functional film formed by reactive sputtering.

[0002]

2. Description of the Related Art In general, as a functional film, for example, an AR film (anti-reflection film) adhered to a panel surface of a cathode ray tube is known. Such a functional film is usually formed by reactive sputtering. That is, in a vacuum chamber, a reactive gas is jetted onto a film base material that is a base of a functional film, and the reactive gas is chemically reacted with a target material, so that a metal oxide film, a metal nitride film, etc. Compound thin film (optical thin film)
By forming a film, a functional film having an antireflection function and light transmittance is formed.

A functional film used for a cathode ray tube has a low reflectance and a high transmittance (for example, a reflectance of 0.5%).
Hereinafter, a transmittance of 90% or more) has been desired.
However, the reflectance and transmittance of the functional film depend on the optical thickness of the optical thin film formed on the film substrate.

For this reason, conventionally, in the production of a functional film, the spectral reflectance after film formation has been measured,
The partial pressure of the reactive gas is adjusted according to the measurement result, thereby adjusting the optical film thickness of the optical thin film. This is because the functional film is composed of a film base and an optical thin film with low light absorption, so it is easy to maintain high transmittance, and the reflectance is controlled by adjusting the optical film thickness of the optical thin film. By doing so, the low reflectance and high transmittance can be naturally satisfied.

[0005]

However, in recent years, low reflectance specific transmittance (for example, reflectance of 0.5% or less,
Functional films (transmittance adjusting films) with a transmittance of 75 ± 2%) are also widely used, and light transmission is becoming more important than anti-reflection functions. If the optical film thickness of the optical thin film is adjusted based on the spectral reflectance as described above, the following problem may occur.

That is, if the optical film thickness of the optical thin film is adjusted based on the spectral reflectance as in the prior art, it is easy to maintain a high transmittance, but it is difficult to control the transmittance. As a result, the desired transmittance may not be satisfied.

On the other hand, the correlation between the reflectance and the transmittance is obtained from past empirical rules, and the reflectance corresponding to the desired transmittance is calculated by simulation based on the correlation. It is also conceivable that the optical film thickness of the optical thin film can be adjusted to obtain a desired transmittance. However, in this case, when there is a change in the specification of the functional film to be manufactured, it is necessary to calculate the correlation between the reflectance and the transmittance or calculate the reflectance by simulation each time. As a result, quick response becomes difficult.

Accordingly, an object of the present invention is to provide a method and an apparatus for producing a functional film, which enable quantitative and rapid control of the transmittance of the functional film.

[0009]

SUMMARY OF THE INVENTION The present invention is a method for producing a functional film devised to achieve the above object. That is, a functional film that forms an optical thin film on the film substrate by ejecting a reactive gas onto the film substrate that is the basis of the functional film and performs reactive sputtering to form the functional film. In the manufacturing method, the spectral transmittance of the functional film after the optical thin film is formed is measured, and the ejection amount when ejecting the reactive gas is varied based on the measurement result of the spectral transmittance. It is characterized by the following.

According to the method of manufacturing a functional film according to the above procedure, the amount of the reactive gas to be ejected thereafter is varied based on the measurement result of the spectral transmittance of the functional film after the optical thin film is formed. . For example, if the measurement result of the spectral transmittance is higher than a desired value, it is considered that the optical film thickness of the optical thin film is thin, so that the ejection amount of the reactive gas is increased,
If the measured result of the spectral transmittance is lower than a desired value, the optical film thickness of the optical thin film is considered to be large, and the amount of the reactive gas ejected is reduced. Since the optical film thickness of the optical thin film is adjusted by the increase or decrease of the ejection amount, the transmittance of the functional film is corrected as a result. That is, the transmittance of the functional film after the formation of the optical thin film can be controlled so as to match the desired value.

The present invention also provides a functional film manufacturing apparatus devised to achieve the above object, comprising: a film feeding means for feeding a film substrate as a basis of a functional film in one direction; A sputtering means for ejecting a reactive gas to the film substrate sent by the means to perform reactive sputtering and form an optical thin film on the film substrate to form the functional film; A transmittance measuring means for measuring the spectral transmittance of the functional film after the film, and variably controlling the amount of reactive gas ejected by the sputtering means based on a result of measurement of the spectral transmittance by the transmittance measuring means. And a gas ejection amount control means.

According to the functional film manufacturing apparatus having the above-described structure, the transmittance measuring means constantly monitors the change in the spectral transmittance of the functional film after the formation of the optical thin film. Even if they do not match, the gas ejection amount control means applies feedback to variably control the reactive gas ejection amount in the sputtering means, so that the optical film thickness of the optical thin film formed by the sputtering means Adjust automatically. For example, if the measurement result of the spectral transmittance is higher than the specified range, the gas ejection amount control means increases the ejection amount of the reactive gas because the optical film thickness of the optical thin film is considered to be thin, and also measures the spectral transmittance. If the result is lower than the desired value, it is considered that the optical film thickness of the optical thin film is large, so that the amount of the reactive gas jetted is reduced. Since the optical thickness of the optical thin film is automatically adjusted by the feedback control by the gas ejection amount control means, the transmittance of the functional film is corrected accordingly. That is, the transmittance of the functional film after the formation of the optical thin film can be controlled so as to match the desired value.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method and an apparatus for producing a functional film according to the present invention will be described below with reference to the drawings. Here, the case where the functional film is attached to the panel surface of the cathode ray tube will be described as an example.

First, the outline of the method for producing a functional film according to the present invention will be described. FIG. 1 is a diagram illustrating an example of a method for producing a functional film according to the present invention.

[0015] The functional film is formed by reactive sputtering. That is, in a vacuum chamber, a reactive gas such as O ₂ gas (oxygen) or N ₂ gas (nitrogen) is jetted to a film base material that is a base of a functional film, and the reactive gas is used as a target material. And a chemical reaction between them and forming an optical thin film such as a metal oxide film or a metal nitride film on the film substrate, thereby forming a functional film having an antireflection function and a light transmitting property.

As a film substrate on which the functional film is based, for example, a long roll film having a certain width is used. Therefore, the reactive gas is ejected onto the film substrate by a plurality of gas jets arranged at appropriate intervals along the width direction so that an optical thin film can be formed over the entire width of the film substrate. From the exit. In other words, the formation of the functional film is performed by ejecting the reactive gas from the plurality of gas ejection ports and moving the film substrate at that time so that the film substrate passes over the arrangement position of the gas ejection ports. By doing.

Up to this point, the manufacturing method described in the present embodiment is substantially the same as the conventional manufacturing method of a functional film. Is different from the conventional one.

That is, in order to control the amount of the reactive gas ejected from the gas ejection port, in the manufacturing method described in this embodiment, first, as shown in FIG. The spectral transmittance (transmittance for monochromatic light) of the functional film 1 immediately after the formation of the optical thin film by the jetting of the reactive gas to be performed is set to a plurality of values along the width direction of the functional film 1. The measurement is performed at the measurement position 2. The measurement of the spectral transmittance at this time may be performed using, for example, a spectrophotometer using a known technique.

Then, from the measurement result of the spectral transmittance, the distribution state of the spectral transmittance in the width direction on the functional film 1 is recognized, for example, as shown in the transmittance before the partial pressure adjustment in FIG. Thereby, it is determined whether or not the value of the spectral transmittance of the functional film 1 after forming the optical thin film matches the desired value, and how much the spectral transmittance varies in the width direction of the functional film 1. You will understand.

At this time, the portion where the measured value of the spectral transmittance is higher than the desired value or the average value of the other measured values is the portion where the optical film thickness of the formed optical thin film is the desired film thickness or other portion. It is considered to be thinner than the film thickness. In addition, the portion where the measured value of the spectral transmittance is lower than the desired value or the average value of other measured values, the optical film thickness of the formed optical thin film is larger than the desired film thickness or the optical film thickness of other portions. It is considered thick.

From this, when the distribution state of the spectral transmittance is recognized, for example, as shown in FIG. 1 (c), the partial pressure of the reactive gas is adjusted in accordance with the recognition result, whereby the optical thin film Adjust the film thickness. That is, in a portion where the measured value of the spectral transmittance is high, the amount of the reactive gas jetted is increased so that the optical film thickness to be formed is increased. In addition, in the portion where the measured value of the spectral transmittance is low, the amount of the reactive gas to be ejected is reduced so that the optical film thickness to be formed becomes thin.

Further, in adjusting the partial pressure of the reactive gas, the following points are taken into consideration. That is, in the reactive sputtering using the reactive gas, the sputtering rate becomes lower as the partial pressure of the reactive gas in the Ar (argon) atmosphere in the vacuum chamber is relatively higher. Conversely, the lower the partial pressure of the reactive gas, the higher the sputter rate. Utilizing such well-known facts, the partial pressure of the reactive gas is appropriately adjusted.

The partial pressure of the reactive gas is adjusted by individually varying the amount of the reactive gas jetted for each of the plurality of gas jet ports corresponding to the measurement of the spectral transmittance at a plurality of locations. Just do it. However, it is possible to adjust the partial pressure of the reactive gas even if several gas jets are used as one unit instead of each gas jet and the amount of the reactive gas jetted is varied for each unit. is there. In this case, it is assumed that each unit ejects the reactive gas to different regions on the film substrate.

The amount of the reactive gas jetted can be varied for each gas jet, or when several gas jets are used as one unit, as described below. You can do it. For example, by changing the diameter of the gas outlet by replacing the attachment attached to the gas outlet or attaching a variable valve mechanism to the gas outlet, the amount of reactive gas ejected can be varied. To make it possible. Another example is to change the flow rate of the reactive gas supplied to each gas outlet or each unit, thereby making the amount of the reactive gas jetted variable.

However, when the reactive gas ejection amount is changed by using a variable valve mechanism that can be controlled from outside the vacuum chamber or a change in the flow rate of the reactive gas, for example, the vacuum chamber is not opened to the atmosphere. The partial pressure of the reactive gas can be adjusted. In other words, since it is not necessary to open the vacuum chamber to the atmosphere for adjusting the partial pressure of the reactive gas,
The environment in the vacuum chamber can be easily maintained.

The adjustment of the partial pressure of the reactive gas is repeatedly performed based on the measurement result of the spectral transmittance until the measurement result substantially matches a desired value. As a result, the functional film 1 formed after the adjustment of the partial pressure of the reactive gas does not require the calculation of the correlation between the spectral transmittance and the optical film thickness of the optical thin film, and the spectral transmittance becomes the desired value. It becomes substantially coincident, and the transmittance distribution thereof can be kept substantially uniform in the width direction of the functional film 1.

Specifically, for example, by adjusting the partial pressure of the reactive gas as shown in FIG. 1C, an optical thin film having a uniform optical film thickness over the width direction can be formed. For example, as shown in the transmittance after the adjustment of the partial pressure in FIG. 1B, the functional film 1 formed after the adjustment of the partial pressure has the spectral transmittance while maintaining the uniformity of the transmittance distribution in the width direction. The value of the ratio is ± 0.0 of the reference value (desired value).
It is possible to keep it within the range of about 1%.

In the above procedure, the recognition of the distribution of the spectral transmittance and the adjustment of the partial pressure of the reactive gas may be performed automatically by a functional film manufacturing apparatus that performs reactive sputtering. Alternatively, the operation may be performed manually by an operator of the manufacturing apparatus.

Next, a manufacturing apparatus for performing the method for manufacturing a functional film according to the above procedure, that is, an apparatus for manufacturing a functional film according to the present invention will be described. FIG.
It is a schematic structure figure showing an example of the manufacturing device of the functional film concerning the present invention.

As shown in the figure, a functional film manufacturing apparatus (hereinafter, referred to as “the present apparatus”) described in the present embodiment includes:
In the vacuum chamber 11 where the reactive sputtering is performed, the film base 1a serving as the base of the functional film 1 can be sent in one direction. Further, a reactive gas ejection nozzle 12 extending along the width direction of the film substrate 1 a in the vacuum chamber 11, a target material 13 disposed with the ejection nozzle 12 interposed therebetween, and a target material 1
A cathode 14 for repelling 3 toward the film substrate 1a, and a partition plate 15 disposed so as to cover the lower side thereof are provided. Among them, the ejection nozzle 12 is provided with a plurality of gas ejection ports 12a arranged at appropriate intervals along the width direction of the film substrate 1a.

In the present apparatus, while moving the film base 1a so that the film base 1a passes over the disposition position of the jet nozzle 12, the gas of the jet nozzle 12 is moved with respect to the film base 1a. A reactive gas is ejected from the ejection port 12a, and the reactive gas chemically reacts with the target material 13 repelled by the cathode 14, thereby forming an optical thin film on the film substrate 1a. 1 is formed.

In addition, the present apparatus is arranged such that the transmission for measuring the spectral transmittance of the functional film 1 is provided near the partition plate 15 in the vacuum chamber 11 and on the downstream side in the traveling direction of the functional film 1. A rate detection sensor 16 is provided. It is assumed that the transmittance detection sensors 16 are provided at a plurality of locations along the width direction of the functional film 1. However, the arrangement intervals and the number of arrangements may be appropriately determined as needed, and are not particularly limited. For example, the transmittance detection sensors 16 may be arranged at equal intervals along the width direction of the functional film 1, but the functional film is considered to have a large variation in the optical film thickness of the optical thin film to be formed. It is also conceivable that the vicinity of one edge is arranged particularly densely.

The plurality of transmittance detection sensors 16 are connected via a signal line 18a to a computer 17 provided outside the vacuum chamber 11 of the apparatus, and notify the computer 17 of the measurement result of the spectral transmittance. It has become.

The computer 17 has a program for recognizing the distribution state of the spectral transmittance of the functional film 1 based on the notification from each transmittance detection sensor 16 and the gas of the ejection nozzle 12 based on the recognition result. A program for instructing the adjustment of the partial pressure of the reactive gas ejected from the ejection port 12a is installed in advance. Further, the computer 17 has an operation means (keyboard or the like) for setting a reference value (desired value) of the spectral transmittance required for adjusting the partial pressure of the reactive gas.

Further, in the present apparatus, a gas distributor with an adjusting function (hereinafter abbreviated as “MFC”) 19 is provided between a supply source of a reactive gas (not shown) and the ejection nozzle 12.
Then, the computer 17 connects the MFC 19 to the signal line 1.
8b, and from the computer 17 to the MF
C19 is instructed to adjust the partial pressure of the reactive gas.

In response to the instruction from the computer 17, the MFC 19 uses the above-described method (for example, a change in the flow rate of the reactive gas) for each gas outlet 12a in the jet nozzle 12 or for some gas jets. Exit 12a
Is used as one unit to vary the amount of reactive gas ejected to the film substrate 1a.
That is, the amount of reactive gas ejected from the ejection nozzle 12 is
It is variably controlled by the computer 17 and the MFC 19.

Therefore, in this apparatus, even when the partial pressure of the reactive gas is adjusted, it is not necessary to open the inside of the vacuum chamber 11 to the atmosphere. That is, it is easy to maintain the environment in the vacuum chamber 11.

Next, an example of a processing operation in the present apparatus having the above-described configuration will be described. FIG. 3 is a flowchart showing an example of a processing operation in the functional film manufacturing apparatus according to the present invention.

As shown in the figure, the functional film 1 is
Is formed, first, the power supply of the cathode 14 is turned on under the condition that the film can be formed (Step 101; hereinafter, the steps are abbreviated as “S”), and the input power to the present apparatus is set (S102). A reactive gas is injected into the vacuum chamber 11 from the ejection nozzle 12 (S103). As a result, the optical thin film is sputtered on the film substrate 1a to form the functional film 1.

However, in this apparatus, in the process, the transmittance, which is an important quality of the functional film 1, is adjusted so as to match a reference value (for example, 75% ± 0.5%). Specifically, in the adjustment, feedback control is performed so that the spectral transmittance of the functional film 1 that is constantly monitored by each transmittance detection sensor 16 is always within the range of the reference value.

This feedback control is performed as follows. First, as a signal exchange, the transmittance detection sensor 16 transmits a time-series spectral transmittance measurement result to the computer 17. Based on the notified data, the computer 17 displays the measurement result of the spectral transmittance of the functional film 1 on the display or the like as an in-line transmittance monitor (S104), and transmits the measurement result of the spectral transmittance to the operation unit in advance. It is determined whether or not it is within the range of the adjustment reference value set in advance (for example, a value set more strictly than the reference value of the main body, such as 75% ± 0.3%) (S105).

As a result of this determination, if the measurement result of the spectral transmittance is within the range of the adjustment reference value, the computer 17 causes the MFC 19 to maintain the partial pressure of the reactive gas at that time.
And the monitoring of the spectral transmittance of the functional film 1 is continuously performed (S1).
06).

On the other hand, when the measurement result of the spectral transmittance exceeds the range of the adjustment reference value, the computer 17 partially adjusts the partial pressure of the reactive gas only at the portion where the adjustment reference value is exceeded. An instruction is given to the MFC 19 to do so. In response to this instruction, the MFC 19 adjusts the partial pressure of the reactive gas, and partially varies the amount of the reactive gas ejected from the ejection nozzle 12 to the film substrate 1a (S107). Then, the transmittance detection sensor 16
The partial pressure of the reactive gas is adjusted until the measurement result of the spectral transmittance obtained by the above becomes within the range of the adjustment reference value (S108).

As the partial pressure adjustment amount at this time, a flow rate change of about 0.1 to 10% with respect to the total flow rate of the reactive gas is appropriate. Therefore, depending on the response amount of the spectral transmittance, the partial pressure adjustment of the reactive gas may be continuously performed a plurality of times.

When the measurement result of the spectral transmittance falls within the range of the adjustment reference value by the partial pressure adjustment of the reactive gas, the computer 17 instructs the MFC 19 to maintain the adjusted partial pressure. The instruction is given, and the spectral transmittance is continuously monitored (S106). When the measurement result of the spectral transmittance exceeds the range of the adjustment reference value, the above-described processing operation is repeated again (S105 to S10).
8) Always give feedback.

Therefore, when the functional film 1 is formed using the present apparatus, the functional film 1 is subjected to feedback control by the transmittance detection sensors 16, the computer 17 and the MFC 19 to control the spectral transmittance and the optical property of the optical thin film. The spectral transmittance falls within the range of the adjustment reference value without having to calculate the correlation with the film thickness, and the transmittance distribution is kept substantially uniform over the width direction of the functional film 1. Will be able to

The present apparatus may realize a security function when performing the above-described feedback control. In other words, the adjusted flow rate of the reactive gas at the time of performing the feedback control differs depending on the set value condition. For example, when the adjusted flow rate exceeds 30% of the total flow rate, or when the feedback control is performed, If the measurement result exceeds the range of the adjustment reference value, it is highly likely that the transmittance has changed due to other factors instead of the optical film thickness of the optical thin film. It may be possible to warn that.

As described above, according to the method and apparatus for manufacturing a functional film described in the present embodiment, based on the measurement result of the spectral transmittance of the functional film 1 after the optical thin film is formed. Since the optical film thickness of the optical thin film is adjusted by varying the amount of the reactive gas jetted out, the transmittance of the functional film 1 is correctly corrected, and as a result, the transmittance of the functional film 1 is adjusted. Can be controlled to match the desired value. That is,
Since the desired transmittance can be satisfied, for example, even when the functional film 1 having the low reflectance and the specific transmittance is formed, it is possible to easily and appropriately cope with this.

In addition, the control described above increases or decreases the amount of reactive gas jetted based on the measurement result of the spectral transmittance.
Since it uses a very simple control algorithm, such as increasing or decreasing it until the desired spectral transmittance is obtained,
For example, there is no need for a preliminary simulation process or the like including the calculation of the correlation between the spectral transmittance and the optical film thickness of the optical thin film. Even if there is, quick response is possible.

In addition, in the method and apparatus for manufacturing a functional film according to the present embodiment, the measurement of the spectral transmittance is performed at a plurality of locations along the width direction of the functional film 1 (a direction substantially orthogonal to the direction of travel). At the same time, the distribution of the amount of the reactive gas jetted in the width direction of the film substrate 1a is changed according to the measurement result at each location, that is, the amount of the reactive gas jetted is partially increased or decreased. Therefore, not only can the transmittance of the functional film 1 match the desired value, but also the transmittance distribution can be maintained substantially uniform over the width direction of the functional film 1.

The uniformity of the transmittance of the functional film 1 is very important especially when the functional film 1 is used by sticking to the panel surface of a cathode ray tube. This is because, for example, when the transmittance distribution in the functional film changes, the brightness of the screen of the cathode ray tube or the uniformity (uniformity) of the display color changes, and as a result, the image quality of the displayed image is reduced. . From this, the functional film 1 formed by the manufacturing method and the manufacturing apparatus described in the present embodiment,
Since the transmittance distribution in the width direction can be kept substantially uniform,
In particular, it can be said to be suitable for sticking to the panel surface of a cathode ray tube.

As in the functional film apparatus described in the present embodiment, the computer 17 and the like automatically adjust the partial pressure of the reactive gas based on the measurement result of the spectral transmittance. In this case, the feedback control is continuously performed, so that the transmittance and the optical film thickness can be more accurately controlled.

Further, since it is not necessary to open the inside of the vacuum chamber 11 to the atmosphere or to manually control the transmittance and the optical film thickness, control during the film forming process (so-called in-line) is possible. Becomes That is,
For example, since reactive sputtering is not interrupted for adjusting the partial pressure of the reactive gas, quick response is possible, and constant quality can be maintained without inputting a large number of personnel. As a result, improvement in production efficiency and cost reduction of the functional film 1 can be expected. Specifically, since it is not necessary to open the vacuum chamber 11 to the atmosphere, it is necessary to clean the vacuum chamber 11 at the time of opening to the atmosphere as in the related art, and to perform vacuum pumping after that.
There is no need to set conditions for optical characteristics when restarting production, etc.
These man-hours can be reduced to about 1/4 of the case of opening to the atmosphere.

In addition, since the in-line control is made possible, the optical film can be continuously formed.
That is, when it is necessary to open the atmosphere in the vacuum chamber 11 or the like,
Since the environment in the vacuum chamber 11 cannot be maintained for a long time, continuous film formation is difficult. However, if the in-line control is enabled, it is easy to appropriately maintain the environment in the vacuum chamber 11. As long as the supply of the film substrate 1a is continued, for example, the target material 1 which is a thin film material is used.
It is possible to perform continuous film formation up to the life of 3. Specifically, as a current ability, continuous film formation of about 26000 m has been realized. However, the continuous film formation length can be further increased by changing the life of the target material 13.

In this embodiment, the case where the functional film is adhered to the panel surface of the cathode ray tube is described as an example, but the present invention is not limited to this.
As long as it is formed by reactive sputtering and has optical transparency, other functional films can be similarly applied.

[0056]

As described above, in the method and the apparatus for manufacturing a functional film according to the present invention, the reactivity in the subsequent film formation is determined based on the measurement result of the spectral transmittance after the film formation. Since the optical film thickness of the optical thin film is adjusted by changing the gas ejection amount, the transmittance of the functional film can be quantitatively and quickly controlled.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams illustrating an example of a method for producing a functional film according to the present invention, wherein FIG. 1A is a schematic diagram illustrating the outline thereof, and FIG. FIG. 4C is a graph showing a specific example, and FIG. 7C is an image diagram showing a specific example of the adjustment of the partial pressure of the reactive gas by the manufacturing method.

FIG. 2 is a schematic configuration diagram illustrating an example of a functional film manufacturing apparatus according to the present invention.

FIG. 3 is a flowchart showing an example of a processing operation in the functional film manufacturing apparatus according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Functional film, 1a ... Film base material, 2 ... Measurement position, 11 ... Vacuum chamber, 12 ... Squirting nozzle, 12a ... Gas outlet, 13 ... Target material, 14 ... Cathode, 16 ...
Transmittance detection sensor, 17 ... computer, 19 ... MFC

Claims (4)

[Claims] An optical thin film is formed on the film base by spraying a reactive gas onto a film base on which the functional film is based to perform reactive sputtering, thereby forming the functional film. In the method for producing a functional film, the spectral transmittance of the functional film after the optical thin film is formed is measured, and the ejection amount when the reactive gas is ejected based on the measurement result of the spectral transmittance. The method for producing a functional film, wherein 2. In the case where reactive sputtering is performed on a film substrate sent in one direction, the measurement of the spectral transmittance is performed at a plurality of locations along a direction substantially orthogonal to the direction of travel of the film substrate. 2. The ejection amount distribution of the reactive gas in a direction substantially orthogonal to a traveling direction of the film substrate according to a measurement result of the spectral transmittance at the plurality of locations. Production method of functional film. 3. A film feeding means for feeding a film base material serving as a basis of the functional film in one direction, and reactive sputtering is performed by ejecting a reactive gas to the film base material sent by the film feeding means. A sputtering means for forming an optical thin film on a film substrate to form the functional film; a transmittance measuring means for measuring a spectral transmittance of the functional film after film formation by the sputtering means; A functional film production apparatus, comprising: a gas ejection amount control means for variably controlling an ejection amount of a reactive gas by said sputtering means based on a measurement result of a spectral transmittance by a rate measurement means. 4. The transmittance measuring means measures the spectral transmittance at a plurality of points along a direction substantially perpendicular to the direction in which the film substrate is fed by the film feeding means. The control means also variably controls the jetting amount distribution of the reactive gas in a direction substantially orthogonal to the traveling direction of the film substrate according to the measurement results of the spectral transmittance at a plurality of locations by the transmittance measuring means. The functional film manufacturing apparatus according to claim 3, wherein: